I have a silver plated spoon warmer in the shape of a nautilus shell on a base. It was manufactured by Mappin Brothers, 222 Regent Street and Londonbridge. The time period of manufacture would have been between 1862 and 1894. The shell looked a bit “brassy” when I got it but has shined up nicely using Silvo Tarnish Guard. The shell is plane/unadorned with any pattern. The mouth where the spoons would be put in is open and unhinged. I have seen similar ones when I googled Mappin Brothers etc. I looking for a valuation for my piece if anyone can help me